Deprecate a bunch of ports that are either abandonware and/or for which no more
public distfiles are available, or for which are -devel version with a more
recent stable version for long
Feature safe: yes

- Update devel/sdl12 to version 1.2.11. Now we employ stock SDL directory
structure (i.e. include/SDL for includes and sdl-config for configuration
binary)
- Update graphics/sdl_ttf to version 2.0.8
- Update graphics/sdl_image to version 1.2.5
- Update audio/sdl_mixer to version 1.2.7
- Update net/sdl_net to version 1.2.6
- Update Mk/bsd.sdl.mk accordingly
- Fix dependent ports to fit the new directory structure and avoid several
API breakages
- Bump up portrevisions for all dependent ports to allow them to be upgraded
by portupgrade/portmaster etc tools
Approved by: kris (portmgr), sem (mentor)